Electrode having membrane with ion selective properties

Abstract

There is provided a novel type of ion selective membrane comprising a non-ion selective carrier, and an ion selective active phase molecule having a hydrophilic segment and a lipophilic periphery. In the preferred embodiment said molecule is a siloxane molecule whose Si-O-Groups are open chain, branch chain or cyclically oriented. These ion selective membranes are useful in the selective detection of alkali- and alkaline-earth metals. There is further provided an electrode for use with such a membrane.

We claim: 
     
       1. An ion selective electrode, being selective with respect to predetermined alkali or alkaline-earth metal ions comprising: (a) a membrane comprising (i) a carrier membrane composed of a non-ion selective carrier material and   (ii) an ion selective material in intimate contact with said carrier, said ion selective material comprising at least one predetermined molecular species exhibiting ion selectivity with respect to predetermined alkali or alkaline-earth metal ions said molecular species being selected from the group consisting of open chain, branch chain or cyclic siloxanes comprising a plurality of Si-O-Groups, the oxygen atoms of said siloxanes having hydrophilic properties and said siloxanes being substituted by lipophilic moieties, further including     (b) electrical conducting means in intimate contact with said membrane.   
     
     
       2. An electrode in accordance with claim 1 wherein the lipophilic substitutents are selected from the group consisting of lower alkyl of 1 to 5 carbon atoms, lower alkenyl of 2 to 5 carbon atoms, cycloalkyl of 4 to 7 carbon atoms, lower alkoxy or halo lower alkoxy of 1 to 5 carbon atoms, phenyl, lower alkyl phenyl of 1 to 5 carbon atoms in the lower alkyl moiety, lower alkylcarboxy of 1 to 5 carbon atoms in the alkyl moiety, lower alkylene dioxy of 2 to 5 carbon atoms, hydrogen and halogen. 
     
     
       3. An electrode in accordance with claim 2 wherein the siloxane moiety is substituted by one, two or three of the substituent moieties set forth in claim 2. 
     
     
       4. An electrode in accordance with claim 1 wherein the carrier is a polymeric material selected from the group consisting of polyvinyl chloride, and nitro cellulose. 
     
     
       5. An electrode in accordance with claim 1 wherein the carrier material is ceramic, sintered glass, felt, woven and non-woven fiber containing fabrics having the ion selective material absorbed thereon. 
     
     
       6. An electrode according to claim 1 further comprising a plasticizer. 
     
     
       7. An electrode according to claim 6 wherein the plasticizer is a polar organic material capable of dissolving the carrier and being substantially non-volatile at ambient temperature and pressure. 
     
     
       8. An electrode in accordance with claim 6 wherein the plasticizer is selected from the group consisting of Tris(2-ethylhexyl phosphate), dinonyl phthalate sebesate derivatives, diphenylether, and ortho nitro phenyl octyl either.